// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/test/python_utils.h"

#include <memory>

#include "base/base_paths.h"
#include "base/command_line.h"
#include "base/environment.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/path_service.h"
#include "base/process/launch.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"

#if defined(OS_MACOSX)
#include "base/mac/foundation_util.h"
#endif

const char kPythonPathEnv[] = "PYTHONPATH";

void AppendToPythonPath(const base::FilePath& dir)
{
    std::unique_ptr<base::Environment> env(base::Environment::Create());
    std::string old_path;
    std::string dir_path;
#if defined(OS_WIN)
    dir_path = base::WideToUTF8(dir.value());
#elif defined(OS_POSIX)
    dir_path = dir.value();
#endif
    if (!env->GetVar(kPythonPathEnv, &old_path)) {
        env->SetVar(kPythonPathEnv, dir_path.c_str());
    } else if (old_path.find(dir_path) == std::string::npos) {
        std::string new_path(old_path);
#if defined(OS_WIN)
        new_path.append(";");
#elif defined(OS_POSIX)
        new_path.append(":");
#endif
        new_path.append(dir_path.c_str());
        env->SetVar(kPythonPathEnv, new_path);
    }
}

bool GetPyProtoPath(base::FilePath* dir)
{
    // Locate the Python code generated by the protocol buffers compiler.
    base::FilePath generated_code_dir;
    if (!PathService::Get(base::DIR_EXE, &generated_code_dir)) {
        LOG(ERROR) << "Can't find " << generated_code_dir.value();
        return false;
    }

#if defined(OS_MACOSX)
    if (base::mac::AmIBundled())
        generated_code_dir = generated_code_dir.DirName().DirName().DirName();
#endif

    // Used for GYP. TODO(jam): remove after GN conversion.
    const base::FilePath kPyProto(FILE_PATH_LITERAL("pyproto"));
    if (base::DirectoryExists(generated_code_dir.Append(kPyProto))) {
        *dir = generated_code_dir.Append(kPyProto);
        return true;
    }

    // Used for GN.
    const base::FilePath kGen(FILE_PATH_LITERAL("gen"));
    if (base::DirectoryExists(generated_code_dir.Append(kGen))) {
        *dir = generated_code_dir.Append(kGen);
        return true;
    }

    return false;
}

#if defined(OS_WIN)
struct PythonExePath {
    PythonExePath()
    {
        // This is test-only code, so CHECK with a subprocess invocation is ok.
        base::CommandLine command(base::FilePath(FILE_PATH_LITERAL("cmd")));
        command.AppendArg("/c");
        command.AppendArg("python");
        command.AppendArg("-c");
        command.AppendArg("import sys; print sys.executable");
        std::string output;
        CHECK(GetAppOutput(command, &output));
        // This does only work if cmd.exe doesn't use a non-US codepage.
        path_ = base::ASCIIToUTF16(output);
        TrimWhitespace(path_, base::TRIM_ALL, &path_);
    }
    base::string16 path_;
};
static base::LazyInstance<PythonExePath>::Leaky g_python_path;
#endif

bool GetPythonCommand(base::CommandLine* python_cmd)
{
    DCHECK(python_cmd);

#if defined(OS_WIN)
    // Most developers have depot_tools in their path, which only has a
    // python.bat, not a python.exe.  Go through cmd to find the path to
    // the python executable.
    // (Don't just return a a "cmd /c python" command line, because then tests
    // that try to kill the python process will kill the cmd process instead,
    // which can cause flakiness.)
    python_cmd->SetProgram(base::FilePath(g_python_path.Get().path_));
#else
    python_cmd->SetProgram(base::FilePath(FILE_PATH_LITERAL("python")));
#endif

    // Launch python in unbuffered mode, so that python output doesn't mix with
    // gtest output in buildbot log files. See http://crbug.com/147368.
    python_cmd->AppendArg("-u");

    return true;
}
